Switch SadTabHelper to use WebContentsUserData.

chrome/browser/ui/sad_tab_helper.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_SAD_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_SAD_TAB_HELPER_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "chrome/browser/tab_contents/web_contents_user_data.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 
 #if defined(OS_MACOSX)
 #include "base/mac/foundation_util.h"
 #endif
 
 #if defined(OS_MACOSX)
 class SadTabController;
 #elif defined(TOOLKIT_VIEWS)
 namespace views {
 class Widget;
 }
 #elif defined(TOOLKIT_GTK)
 class SadTabGtk;
 #endif
 
 // Per-tab class to manage sad tab views.
 class SadTabHelper : public content::WebContentsObserver,
-                     public content::NotificationObserver {
+                     public content::NotificationObserver,
+                     public WebContentsUserData<SadTabHelper> {
  public:
-  explicit SadTabHelper(content::WebContents* web_contents);
   virtual ~SadTabHelper();
 
   // Platform specific function to determine if there is a current sad tab page.
   bool HasSadTab() const;
 
 #if defined(TOOLKIT_VIEWS)
   views::Widget* sad_tab() { return sad_tab_.get(); }
 #endif
 
  private:
+  explicit SadTabHelper(content::WebContents* web_contents);
+  static int kUserDataKey;
+  friend class WebContentsUserData<SadTabHelper>;
+
   // Platform specific function to get an instance of the sad tab page.
   void InstallSadTab(base::TerminationStatus status);
 
   // Overridden from content::WebContentsObserver:
   virtual void RenderViewGone(base::TerminationStatus status) OVERRIDE;
 
   // Overridden from content::NotificationObserver:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
@@ skipping 13 matching lines @@
 #elif defined(TOOLKIT_VIEWS)
   scoped_ptr<views::Widget> sad_tab_;
 #elif defined(TOOLKIT_GTK)
   scoped_ptr<SadTabGtk> sad_tab_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(SadTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_SAD_TAB_HELPER_H_